The official park app covers them, but there's no dedicated tour just for the Three Sisters.

Not really, and you don’t need one.

The Three Sisters Islands are part of Niagara Falls State Park. The park’s own free app (search “Niagara Falls State Park” in your app store) includes an audio tour that hits all the key stops, including the islands. It’s well-produced, works offline, and points out the history and geology without getting too touristy.

If you want something more polished, VoiceMap has a guided walk called “Niagara Falls State Park” that also covers the islands. Same deal — you get the islands as part of the bigger loop. Pay once, download it, walk at your own pace.

What you don’t need is a stand-alone app for three tiny islands. They’re connected by footbridges, you can see all three in 20 minutes, and the signage is decent on its own. If you’re the type who wants every fact narrated, grab the VoiceMap tour. If you just want to wander and read a few plaques, skip the app entirely.

The islands are small. You won’t get lost.